# NTSB ERA14LA022: Piper PA-31-350, N555GK, Franklin, NC, October 17, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 17, 2013, 12:30 local (16:30 UTC) - Place: Franklin, NC - Coordinates: 35.222221, -83.419998 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.2222&lon=-83.4200&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 8 uninjured - Status: Completed, report May 13, 2015 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - NTSB case key (mKey): 88305 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA14LA022 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/88305/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=88305 - Page: https://openairdocs.org/ntsb/ERA14LA022 ## Probable cause The failure of the left main landing gear brake line during landing due to the loss of hydraulic fluid. Contributing to the accident was a fatigue crack through the brake line that had formed due to contact with a swaged sleeve as a result of exfoliation corrosion. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: landing gear brakes system](https://openairdocs.org/ntsb-findings/01023240): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Piper PA-31-350, 1 case](https://openairdocs.org/ntsb-findings/01023240/cases.md?model=7103110), [All aircraft, 92 cases](https://openairdocs.org/ntsb-findings/01023240/cases.md) - [Landing gear system: landing gear brakes system](https://openairdocs.org/ntsb-findings/01023240): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Piper PA-31-350, 1 case](https://openairdocs.org/ntsb-findings/01023240/cases.md?model=7103110), [All aircraft, 92 cases](https://openairdocs.org/ntsb-findings/01023240/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft inspection event](https://openairdocs.org/ntsb-events/050); cases with it: [Piper PA-31-350, 2 cases](https://openairdocs.org/ntsb-events/050/sequence.md?model=7103110), [All aircraft, 229 cases](https://openairdocs.org/ntsb-events/050/sequence.md) - [Prior to flight: Preflight or dispatch event](https://openairdocs.org/ntsb-events/030); cases with it: [Piper PA-31-350, 2 cases](https://openairdocs.org/ntsb-events/030/sequence.md?model=7103110), [All aircraft, 355 cases](https://openairdocs.org/ntsb-events/030/sequence.md) - [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Piper PA-31-350, 6 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=7103110), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Piper PA-31-350, 8 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=7103110), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-31-350, 18 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7103110), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that, during the preflight inspection, he checked both the left and right brake reservoirs for proper servicing, and he found that they were ready for flight. During the landing roll, the pilot applied the left and right brake pedals; however, the left brake did not respond, and the airplane departed the right side of the runway. Postaccident examination of the airplane revealed that there was a hydraulic fluid leak in the left main landing gear brake line. Further examination revealed that the brake line failed due to a fatigue crack that had propagated through the cross-section of the brake line, which resulted in the hydraulic fluid leak. The fatigue cracking was likely due to the detachment of the swaged compression sleeve and nut from the brake line due to exfoliation corrosion. The exfoliation corrosion likely resulted from or was exacerbated by consistent introduction of water and contact between two the different metals in the aluminum sleeve and the stainless steel brake line. A review of the airplane's maintenance records revealed that the airplane's last annual inspection occurred about 3 months before the accident. According to the mechanic who performed the inspection, he performed a visual inspection of the brake system for looseness, leakage, and corrosion and physically checked the tightness of the "B" nut at the brake caliper in accordance with the 100-hour phase checklist; however, he did not note any problems with the left brake line. ## Factual narrative Brake System The airplane was equipped with a hydraulic fluid braking system that included two independent wheel brakes actuated by two separate brake master cylinders, one each for the left and right brake. A hydraulic fluid reservoir, separate from the main hydraulic system, supplied fluid to each cylinder. From the cylinders, hydraulic fluid was routed through hoses and lines to a parking brake valve, located in the forward cabin, through the cabin and wings and to the left and right main landing gear brake assemblies. The brake lines were composed of type 304 stainless steel and attached to a brake caliper via an aluminum swaged sleeve that was compressed behind a nut. Depression of the brake pedal actuated a piston rod in the master cylinder, which applied hydraulic pressure to the brake caliper pistons. Release of the pedal permitted the piston rod to be back-driven by a spring, which in turn released brake pressure at the wheel. Inspection and Maintenance Information According to the airplane's mechanic, he followed the PA-31-350 100 hour phase inspection checklist during the airplane's last annual inspection. He performed a visual inspection for leakage and corrosion and physically checked the tightness of the "B" nut at the brake caliper. The airplane owner reported that the landing gear was cleaned about twice a month with a degreaser. The landing gear was then rinsed with soap and water after each chemical application. Review of the make and model airplane preflight inspection section of the pilot's operating handbook stated, "Left Wing – (12) Landing gear – condition, strut inflation, micro switches, tires, brakes, gear door." Materials Laboratory The left brake line and "B" nut were sent to the NTSB Materials Laboratory for examination. Metallurgical examination revealed fatigue striations at the end of the brake line consistent with fatigue cracking. The swaged sleeve exhibited intergranular cracking consistent with exfoliation corrosion. Chemical examination of the brake line tube revealed that it was consistent with manufacturer's specifications. The composition of the aluminum 2024 swaged sleeve was also consistent with manufacturer's specification. The twin-engine, retractable-gear, low wing, all metal multi-engine powered airplane, serial number 31-7405456, was manufactured in 1974. It was powered by two Lycoming LTI0-540, 350-horsepower engines. A review of the aircraft maintenance records revealed the airplane's most recent annual inspection was completed on July 9, 2013, at an aircraft total time of 7552.2 hours, which was 22 hours prior to the accident. According to an airframe logbook entry dated July 9, 2013, "placed aircraft on jacks and performed landing gear functional and emergency operational checks. Lubricated landing gear system." The airport was equipped with a single paved runway, designated 07/25. The runway was asphalt, and measured 75 feet by 5,000 feet. Airport elevation was 2,034 feet above mean sea level.On October 17, 2013 about 1230 eastern daylight time, a Piper PA-31-350, N555GK, operated by a private individual, was substantially damaged while landing at Macon County Airport (1A5) Franklin, North Carolina. The airline transport pilot and seven passengers were not injured. The flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Instrument meteorological conditions prevailed and an instrument flight plan was filed for the flight that departed Flagler County Airport (XFL) Palm Coast, Florida at 1100. The pilot stated that during the pre-flight inspection of the airplane, both the left and right brake reservoirs were checked for proper servicing and were found to be ready for flight. While landing at 1A5, the pilot selected the gear to the "DOWN" position and pumped the brakes to confirm they were functioning normally before landing. As the airplane touched down, he applied the brakes, but the "left brake went to the floor." The pilot utilized left rudder and minimal usage of the right brake to stay on runway centerline. At 20 knots, the right brake "locked up", the airplane departed the right side of the runway, and collided with a ditch. The hobbs meter showed 7,754 hours at the time of the accident. The Federal Aviation Administration did not conduct an on-scene examination of the airplane. Photographs taken by the 1A5 airport manager revealed substantial damage to the left winglet and to the left wing spar. The airport manager reported a pool of red fluid on the ground beneath the left main landing gear that was consistent with aviation brake fluid, and that the left wheel brake reservoir was empty. There was also red fluid seeping from the "B" nut fitting that tightens the hydraulic brake line to the brake caliper. A 10 year historical review of the FAA Service Difficulty Report database and Piper service bulletins did not reveal any brake line failures or modifications. A section of the left brake line with the "B" nut and ferrule fitting attached was removed and sent to the National Transportation Safety Board Materials Laboratory for further examination. The 1235 automated weather observation at 1A5 included winds calm, scattered clouds 800 feet, broken clouds 1700 feet, overcast clouds 3800 feet, visibility 7 statute miles, temperature 17 degrees C, dew point 16 degrees C, and an altimeter setting of 29.98 inches of mercury. FAA information indicated that the pilot held an airline transport certificate with ratings for multi-engine land, single engine sea. The pilot also held a flight instructor certificate with ratings for airplane multi-engine, instrument airplane, and instrument helicopter. The pilot reported a total flight experience of 30,000 hours, including 3,000 hours in the accident airplane make and model. His most recent flight review was completed June 26, 2013, and his most recent FAA second-class medical certificate was issued on September 18, 2013. ## Aircraft - Registration: [N555GK](https://openairdocs.org/deregistered/N555GK-2018-12-03), registration cancelled 2018-12-03, S/N 31-7405456, built 1974 (OpenAirDocs) - Reported make and model: PIPER PA-31-350 - Registry model: [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350) (registry code 7103110) (OpenAirDocs) - Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 31-7405456 - Year built: 1974 - Airframe hours: 7574 - Engines: LYCOMING TI0-540 SER 310 horsepower reciprocating; LYCOMING TI0-540 SER 310 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Lunsford Air Consulting Inc - Registered owner: Lunsford Air Consulting Inc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 9, 2013, 22 hours before - Departed: YFL, Palm Coast, FL - Destination: 1A5, Franklin, NC - Flight plan: IFR - Airport: 1A5, Macon County Airport, runway 25, 5,000 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: none; flight instructor, airline transport; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review June 26, 2013; seat: left; restraint: 4-point; flight hours: 30,000 total, 3,000 in this make and model, 29,500 as pilot in command, 300 in the last 90 days, 50 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 7 statute miles - Lowest ceiling: 1,700 ft broken - Temperature: 63 °F, dew point 61 °F - Altimeter: 29.97 inHg - Observed at: 1A5 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20131017020729A](https://openairdocs.org/incident/20131017020729A), Oct 17, 2013: Piper PA-31-350, Franklin, NC, Substantial damage. Per airport manager at the scene. Aircraft landed and veered off the right side of the runway and nose gear collapsed, damage to props and wrinkle in left wing… ## Docket (14 files) The files NTSB released with the investigation on April 2, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=88305. 7.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40403761&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Weather Reports and Records (item 2, .PDF, 129 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40402668&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF - Materials Laboratory Factual Report (item 3, .PDF, 9 photos, 2.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424380&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report-Master.PDF - Pilot Statement (item 4, .PDF, 280 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424382&FileExtension=.PDF&FileName=Pilot%20Statement-Redacted.PDF - Record of Conversations (item 5, .PDF, 157 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424383&FileExtension=.PDF&FileName=Record%20of%20Conversations-Master.PDF - Maintenance Records (Excerpts) (item 6, .PDF, 180 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424384&FileExtension=.PDF&FileName=Maintenance%20Records%20(Excerpts)-Redacted.PDF - Aircraft Preflight Inspection Checklist (item 7, .PDF, 350 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424385&FileExtension=.PDF&FileName=Aircraft%20Preflight%20Inspection%20Checklist-Redacted.PDF - Excerpt from Piper Annual Inspection Checklist (item 8, .PDF, 135 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424386&FileExtension=.PDF&FileName=Excerpt%20from%20Piper%20Annual%20Inspection%20Checklist-Master.PDF - Release of Aircraft Wreckage (item 9, .PDF, 141 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424387&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage-Redacted.PDF - Photo 1 - Airplane at Rest (Courtesy of Airport Manager) (item 10, .PDF, 398 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424388&FileExtension=.PDF&FileName=Photo%201%20-%20Airplane%20at%20Rest%20(Courtesy%20of%20Airport%20Manager)-Master.PDF - Photo 2 - Left Wing (Courtesy of Airport Manager) (item 11, .PDF, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424389&FileExtension=.PDF&FileName=Photo%202%20-%20Left%20Wing%20(Courtesy%20of%20Airport%20Manager)-Master.PDF - Photo 3 - Left Wheel Brake Assembly (Courtesy of Airport Manager) (item 12, .PDF, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424390&FileExtension=.PDF&FileName=Photo%203%20-%20Left%20Wheel%20Brake%20Assembly%20(Courtesy%20of%20Airport%20Manager)-Master.PDF - Photo 4 - Expanded View of Left Wheel Brake Assembly (Courtesy of Airport Manager) (item 13, .PDF, 61 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424391&FileExtension=.PDF&FileName=Photo%204%20-%20Expanded%20View%20of%20Left%20Wheel%20Brake%20Assembly%20(Courtesy%20of%20Airport%20Manager)-Master.PDF - Photo 5 - Expanded View of Brake Line Fitting (Courtesy of Airport Manager) (item 14, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40424392&FileExtension=.PDF&FileName=Photo%205%20-%20Expanded%20View%20of%20Brake%20Line%20Fitting%20(Courtesy%20of%20Airport%20Manager)-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.